Abstract: A screening machine of the type used to separate or classify mixtures of solid particles of different sizes includes a fixed base and a perforate screen mounted for movement relative to the base during a screening operation. The screens are pre-tensioned and mounted in a perimeter frame for separating various granular and particulate material. The frame is slid into the side of the machine in a direction parallel with two opposing bevel lips at the ends of the frame which mate in the screening machine with a complementary channel such that when the screen is raised into sealing contact in the screening machine, the bevel ends of the screen panel frame align the screen panel in the machine. The bevels on the screen panel frame provide a positive sealing surface for contact with the adjacent portions of the channel to prevent product from escaping off of the screen during use.

Abstract: A screening machine includes a vibratory carrier and a vibratory drive operatively coupled to the vibratory carrier for imparting vibratory motion thereto. The screening machine includes a screen assembly selectively coupled to the vibratory carrier so that the vibratory motion is transmitted to the screen assembly. A sealing mechanism including at least one rotary cam having a cam surface and at least one actuator being accessible to a user of said screening machine is coupled to the rotary cam. Actuation of the actuator to rotate the cam urges the screen assembly and the carrier into sealing engagement with a confronting surface of the screening machine. The screening machine further includes at least one stop positioned relative to the sealing mechanism to limit rotational movement of the rotary cam in at least one direction.

Abstract: A screening machine of the type used to separate or classify mixtures of solid particles of different sizes includes a fixed base and a perforate screen mounted for movement relative to the base during a screening operation. The screens are pre-tensioned and mounted in a perimeter frame for separating various granular and particulate material. The frame is slid into the side of the machine in a direction parallel with two opposing bevel lips at the ends of the frame which mate in the screening machine with a complementary channel such that when the screen is raised into sealing contact in the screening machine, the bevel ends of the screen panel frame align the screen panel in the machine. The bevels on the screen panel frame provide a positive sealing surface for contact with the adjacent portions of the channel to prevent product from escaping off of the screen during use. The sealing contact of the screen panel is enhanced by a seal member on the screen panel.

Abstract: A screening machine of the type used to separate or classify mixtures of solid particles of different sizes includes a fixed base and a perforate screen deck mounted for movement relative to the base during a screening operation. Leaf springs connect the tail end of the screen deck to the fixed base so that the leaf springs support the tail end of screen deck for movement relative to the base. The leaf springs are oriented horizontally to avoid introducing vertical movement to the screen deck as it moves to and from the head and tail ends. The leaf springs are offset or deflected when the machine is at rest or in the neutral mid-point of its stroke. This arrangement advantageously utilizes the bias of the leaf springs to accelerate, assist or enhance movement of the screen deck during portions of its stroke and likewise to decelerate, hinder or retard the movement during other portions of its stroke. With an appropriate offset, an increase in the effectiveness of the screening process (i.e.

Abstract: A screening machine of the type used to separate or classify mixtures of solid particles of different sizes includes a fixed base and a perforate screen deck mounted for movement relative to the base during a screening operation. Leaf springs connect the tail end of the screen deck to the fixed base so that the leaf springs support the tail end of screen deck for movement relative to the base. The leaf springs are oriented horizontally to avoid introducing vertical movement to the screen deck as it moves to and from the head and tail ends. The leaf springs are offset or deflected when the machine is at rest or in the neutral mid-point of its stroke. This arrangement advantageously utilizes the bias of the leaf springs to accelerate, assist or enhance movement of the screen deck during portions of its stroke and likewise to decelerate, hinder or retard the movement during other portions of its stroke. With an appropriate offset, an increase in the effectiveness of the screening process (i.e.

Abstract: A clamp for securing a removable cover on a screening machine is an over-center mechanical clamp which includes two distinct clamping force adjustment mechanisms. A first clamping force adjustment mechanism includes a plurality of clamping positions on a support bracket mounted on the cover. The clamp handle assembly is selectively positioned in one of the clamping positions on the support bracket to provide incrementally different clamping force levels. Additionally, irrespective of the clamping position, rotation of a threaded rod of the clamp adjusts the clamping force. A force level indicator is provided on the clamp to indicate the clamping force produced by the clamp.

Abstract: A screen frame and screen are secured into sealing engagement within a screening machine by a screen frame sealing mechanism and method which allows the user to simultaneously raise an entire side of the screen frame into sealing engagement. Advantageously, the entire screen frame can be raised into sealing engagement to prevent the escape of fine material being screened and avoid metal-to-metal contact during the screening process from a single location.

Abstract: A mounting structure for a screen frame and/or a top cover to a vibratory frame of a screening machine requires only an initial one time adjustment and includes a pair of elastomeric restraints each including a compressible bumpers on a head-end of the screen frame or top cover and a pair of compressible rollers on a foot-end of the screen frame or top cover. The screening machine mounting structure accounts for the manufacturing tolerances between the screen frame or top cover and the vibratory box frame to provide a snug fit. The rollers allow for easy screen frame or top cover installation and removal and prevent metal-to-metal contact between the respective components which generates wear and noise during operation. Further, the mounting structure according to this invention can be retrofittable into existing screening machines as well as being original equipment and is useful for securing other components of the screening machine in addition to the screen frame and top cover.

Abstract: A coupling for directing a stream of particles falling from a feed spout through an opening on the top cover of the screen box of a screening machine. An upper diaphragm seals the feed spout within the mouth of a funnel. A lower diaphragm seals the funnel discharge opening within the top cover opening. Both diaphragms are flexible and permit the funnel to tilt axially and accommodate movement of the top cover opening with respect to the feed spout. Optionally, a gimble may support the funnel and diaphragms and thereby relieve the diaphragms from the weight of the coupling.

Abstract: A screening machine of the moving base type has an oscillating force reducer and a single counterbalance drive, with the weight of the drive counterbalance sized to underbalance the longitudinal reaction force exerted by the deck on the drive shaft, but to substantially overbalance the lateral reaction force exerted by the deck on the drive shaft. The weight of the force reducer, the spring constant of the spring which oscillates the force reducer, and overall cost are surprisingly reduced.

Abstract: The screening efficiency of a gyratory screening machine, of the type having a moving base, is significantly increased by mounting to the base a spring/mass system which is tuned so that operation of the machine drive produces amplified movement of the mass along at least one of two perpendicular axes on which the base moves. Movement of the mass reduces the net force on the base along the axis on which the mass oscillates. The reaction force of the machine drive on the base along the other of the two perpendicular axes may be offset by a rotary counterbalance operated by the drive. Movement of the base relative to the ground is thereby reduced, and movement of the screen deck relative to ground is increased. This both increases the effectiveness of the screening motion and decreases the total reaction force transmitted through the base.

Abstract: A dust seal connector for accommodating the relative movement between the enclosed, moving screen box of a screening machine, and a fixed particle inlet or outlet conduit connected to the screen box. The relative movement occurs as sliding motion between a suspended flat slide plate and a wear ring below the slide plate, with which the plate is facially engaged. The plate is connected upwardly by an enclosed particle passage to the conduit or box member from which it is suspended, and communicates downwardly with an opening in the ring for the flow of particles. In a preferred embodiment the particles flow through an axially compressed corrugated sleeve which connects the plate to the member from which it is suspended, compression of the sleeve biasing the ring and plate together to maintain a sliding dust seal between them.

Abstract: The size ranges of particles separated on a stack of sieves of different mesh sizes is measured automatically. The stack is clamped together and shaken as a unit to separate the respective fractions, following which the sieves are sequentially separated from the stack and inverted one at a time to dump the fraction retained on each, onto a scale. Each fraction is weighed separately and their relative proportions can be calculated automatically. In a preferred embodiment the sieves are individually cantilevered from a vertical conveyor. The sieves are inverted one by one to dump their contents by advancing them around a horizontal roll at a lower end of the conveyor.

Abstract: Disclosed is a clamp for securing the top cover of a screening machine. Clamping is not subject to galling or seizing and the force exerted is not temperature or displacement dependent. The clamp is air pressure operated, with super-atmospheric pressure being applied for clamping and venting to atmosphere or sub-atmospheric pressure being applied to release the clamp. The clamp is mounted for easy swing away movement when not in use so as to permit the top cover to be removed. Multiple clamps may be simultaneously operated from a common manifold.

Abstract: An apparatus for automatically removing particulate matter from a weighing pan of a particle-size analyzer. The apparatus includes a weighing pan having a hinged door to provide a discharge outlet for the particular matter and a wiper blade assembly for clearing the particulate matter from the weighing pan. The apparatus further includes a driving mechanism, preferably a rodless cylinder, for operating the wiper assembly in the weighing pan.

Abstract: Disclosed is a ball cleaner for a screening machine in which the ball cages are presented by a molded plastic insert having integral intersecting longitudinal walls and cross walls. The weight of material being screened on the screen which overlies the insert is not carried by the insert but rather by a separate support beneath it. The support comprises a peripheral frame and joists within the frame which directly underlie at least the longitudinal walls of the insert. The insert completely isolates the frame from the erosive action of the cleaning balls and can be replaced separately from the frame.

Abstract: Disclosed is a clamp for securing the cover of a screening machine. The clamp is air pressure operated, both to apply clamping force and to retract or swing the clamp out of the way when it is open. Super-atmospheric pressure is applied for clamping; subatmospheric pressure is applied to swing the clamp away. Multiple clamps may be simultaneously operated by pressure or vacuum from a common manifold.

Abstract: A self-locking clamp has a handle which locks to a non-rotating member if the handle starts to turn while in clamping use. The clamp has a retractable collar which is splined to the handle and is biased toward locking engagement with a sleeve that in turn seats against the member to be clamped. The collar can be held retracted from the sleeve for tightening and loosening the clamp.

Abstract: A screen deck having spaced, canted parallel slats which present screening slots between them, wherein the slats are mounted on pedestals that are positioned and aligned by parallel rods which extend transversely through the pedestals. The pedestals are spaced apart by spacers between them, the spacers being held in place by the rods. Slat mounting is facilitated and slot width uniformity is improved by use of the pedestals.

Abstract: A flexible connector for screening machines comprises an assembly of a plurality of generally cylindrical, flexible collars. Each collar has an annular endwise bead on a first circumferential end and an annular endwise opening groove within an endwise surface of a second circumferential end. The collars are connected by applying force in an axial direction to adjacent and aligned collars to seat and secure the bead of one collar into the groove of an adjacent collar to form a tube along an axis of connection between a particle chute and a movable screen frame.